What is the primary purpose of the Glasgow Coma Scale (GCS)?

The primary purpose of the Glasgow Coma Scale (GCS) is to evaluate a patient's level of consciousness. This scale provides a standardized method for assessing a patient's responsiveness and neurological function, particularly after a head injury or in critical care settings. The GCS is based on three components: eye opening, verbal response, and motor response. Each of these components is scored, and the total score helps healthcare professionals quickly gauge the severity of the patient's condition and potential need for immediate intervention.

The other options represent various assessments that are not the focus of the GCS. While assessing respiratory rate is crucial in critical care, it is not a component of the GCS. Determining blood volume status is typically done through different clinical assessments and monitoring rather than the GCS. Additionally, measuring pain intensity is addressed through various pain scales, which are separate from the consciousness evaluation provided by the GCS. Thus, the GCS is specifically designed for assessing consciousness levels, making this option the most accurate choice.